Share 'Blogs and how to focus?'

I have a general question in regard to a blog I would like to start. Like most people, my interests are varied and I have always wanted a group blog that reflected that. Is there a way to do a group blog that has more than one topic, perhaps with six or seven focus areas, and not have one or two of the more controversial subjects consume the entire purpose of the blog? Or is it just a bad idea…